(a) Field of Disclosure
The present disclosure of invention relates to a liquid crystal display.
(b) Description of Related Technology
Liquid crystal displays (LCD's) are one of the most common types of flat panel displays currently in use. An LCD is a display device in which liquid crystal molecules of a liquid crystal layer are rearranged by applying an electric field through the liquid crystal layer whereby the LC molecules are re-oriented and their optical properties are used to control a transmitted light amount. The electric field through the liquid crystal layer is typically formed by applying a voltage between a so-called, pixel-electrode and an opposed common electrode. In one type of LCD, the pixel-electrode and opposed common electrode are respectively disposed on spaced apart substrates. In a second type of LCD, the pixel-electrode and opposed common electrode are integrally disposed on a same substrate.
The liquid crystal types of display have advantages such as that of being easily made thin, but they also generally have a disadvantage in that side visibility of images produced by them are poor as compared with front (face on) visibility. As a result, various liquid crystal device layout arrangements and driving methods have been developed in order to try and solve the side visibility problem. One such method for providing a wide viewing angle for a liquid crystal display involves placing the pixel electrode and the common electrode on one same substrate.
However, during manufacturing of such devices having the pixel electrode and the common electrode on the same substrate, new problems develop. A first such problem is that optical transmittance may be reduced by a haze effect due to a chemical reduction reaction which may take place between two of the electrodes. Further, if the pixel electrode is formed to directly contact the drain electrode of a corresponding thin film transistor (TFT) or of another such switching element, the drain electrode may be damaged by an etchant used to pattern the pixel electrode. Further, in order to connect the common electrode with a common voltage line that is used for transferring a common electrode voltage thereto, a contact hole may need to be formed, and as a result, an aperture ratio of the liquid crystal display is deteriorated. Additionally, the common voltage transferring line and the gate line may become shorted to each other, for example due to static electricity generated while forming the drain contact hole.
Meanwhile, as sizes of liquid crystal displays generally increase (due to market desires), the number of the data lines provided on the one substrate tends to increase and the cost for a data driver used to drive those data lines also tends to increase, thereby increasing the overall manufacturing cost of the liquid crystal display.
It is to be understood that this background of the technology section is intended to provide useful background for understanding the here disclosed technology and as such, the technology background section may include ideas, concepts or recognitions that were not part of what was known or appreciated by those skilled in the pertinent art prior to corresponding invention dates of subject matter disclosed herein.